 /*******************************************************************************
  * Copyright (c) 2003, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.internal.runtime;

 import java.lang.reflect.Method ;
 import org.eclipse.core.runtime.*;
 import org.osgi.framework.Bundle;

 /**
  * This class isolates calls to the backward compatibility layer.
  * It uses reflection so it can be loaded with success even in the absence of
  * the compatibility plugin.
  *
  * @deprecated Marked as deprecated to suppress deprecation warnings.
  */
 public class CompatibilityHelper {
     private static final String OPTION_DEBUG_COMPATIBILITY = Platform.PI_RUNTIME + "/compatibility/debug"; //$NON-NLS-1$
 public static final boolean DEBUG = Boolean.TRUE.toString().equalsIgnoreCase(InternalPlatform.getDefault().getOption(OPTION_DEBUG_COMPATIBILITY));
     public static final String PI_RUNTIME_COMPATIBILITY = "org.eclipse.core.runtime.compatibility"; //$NON-NLS-1$
 private static Bundle compatibility = null;

     public synchronized static void nullCompatibility() {
         compatibility = null;
     }
     
     public synchronized static Bundle initializeCompatibility() {
         // if compatibility is stale (has been uninstalled or unresolved)
 // then we try to get a new resolved compatibility bundle
 if (compatibility == null || (compatibility.getState() & (Bundle.INSTALLED | Bundle.UNINSTALLED | Bundle.STOPPING)) != 0)
             compatibility = org.eclipse.core.internal.runtime.InternalPlatform.getDefault().getBundle(PI_RUNTIME_COMPATIBILITY);
         return compatibility;
     }

     public static void setPlugin(IPluginDescriptor descriptor, Plugin plugin) {
         //Here we use reflection so the runtime code can run without the compatibility plugin
 if (initializeCompatibility() == null)
             throw new IllegalStateException ();

         try {
             Method setPlugin = descriptor.getClass().getMethod("setPlugin", new Class [] {Plugin.class}); //$NON-NLS-1$
 setPlugin.invoke(descriptor, new Object [] {plugin});
         } catch (Exception e) {
             //Ignore the exceptions
 }
     }

     public synchronized static IPluginDescriptor getPluginDescriptor(String pluginId) {
         //Here we use reflection so the runtime code can run without the compatibility
 initializeCompatibility();
         if (compatibility == null)
             throw new IllegalStateException ();

         Class oldInternalPlatform = null;
         try {
             oldInternalPlatform = compatibility.loadClass("org.eclipse.core.internal.plugins.InternalPlatform"); //$NON-NLS-1$
 Method getPluginDescriptor = oldInternalPlatform.getMethod("getPluginDescriptor", new Class [] {String .class}); //$NON-NLS-1$
 return (IPluginDescriptor) getPluginDescriptor.invoke(oldInternalPlatform, new Object [] {pluginId});
         } catch (Exception e) {
             if (DEBUG) {
                 String msg = "Error running compatibility code"; //$NON-NLS-1$
 IStatus error = new Status(IStatus.ERROR, Platform.PI_RUNTIME, 1, msg, e);
                 InternalPlatform.getDefault().log(error);
             }
             //Ignore the exceptions, return null
 }
         return null;
     }

     public synchronized static void setActive(IPluginDescriptor descriptor) {
         initializeCompatibility();
         if (compatibility == null)
             throw new IllegalStateException ();

         try {
             Method setPlugin = descriptor.getClass().getMethod("setActive", null); //$NON-NLS-1$
 setPlugin.invoke(descriptor, null);
         } catch (Exception e) {
             //Ignore the exceptions
 }
     }

     public synchronized static boolean hasPluginObject(IPluginDescriptor descriptor) {
         initializeCompatibility();
         if (compatibility == null)
             throw new IllegalStateException ();

         Boolean result = Boolean.FALSE;
         try {
             Method setPlugin = descriptor.getClass().getMethod("hasPluginObject", null); //$NON-NLS-1$
 result = (Boolean ) setPlugin.invoke(descriptor, null);
         } catch (Exception e) {
             //Ignore the exceptions
 }
         return result.booleanValue();
     }
 }

